Electron and proton transfers at diiron dithiolate sites relevant to the catalysis of proton reduction by the [FeFe]-hydrogenases

This review focuses on electron and proton transfers involving hexacarbonyl and substituted {2Fe2S} complexes inspired from the active site of the [FeFe]-hydrogenases ([FeFe]H2ases), and on different mechanisms by which the synthetic models catalyze the reduction of protons. Selected aspects of the mechanisms proposed for the biological process on the basis of DFT calculations are also briefly presented.